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Bioclimatic Architecture: Benefits and Famous Examples

Guide to bioclimatic architecture: what it is and why it is so important in the era of climate change and sustainable construction

Bioclimatic architecture is an innovative and conscious response to the issues related to urbanization. In an era marked by growing concerns about climate change, limited availability of natural resources, and environmental pollution, bioclimatic architecture emerges as a valuable resource to reduce the negative impact of human activities on the ecosystem.

It aims not only to mitigate the environmental damage caused by constructions but also aspires to promote a harmonious and regenerative relationship between humans and nature.

What is bioclimatic architecture?

Bioclimatic architecture is a type of architecture where sustainability reigns supreme: it permeates every aspect, from design to building construction. The bioclimatic approach leverages the morphological characteristics and the climate of the location, using local materials. For its functioning, it harnesses renewable energy sources (solar radiation, wind, flora, watercourses, etc.).

Therefore, we can say that bioclimatic architecture is based on an ecologically correct attitude towards the anthropic-environmental ecosystem, aiming to integrate human activities with natural phenomena to improve the quality of life.

The 3 most important principles on which bioarchitecture is based are:

  • quality of life;
  • energy saving;
  • environmental sustainability.

Bioclimatic architecture: some examples

In Italy and around the world, there are numerous examples of bioarchitecture that demonstrate the effectiveness of this approach. Here are some:

  • Frank Lloyd Wright’s Fallingwater house;
  • the California Academy of Sciences in San Francisco;
  • The Edge in Amsterdam;
  • the Energy Box (L’Aquila);
  • the Zisa Castle in Palermo;
  • Le Corbusier’s rooftop garden;
  • green facades.

Bioclimatic architecture: projects worldwide

Frank Lloyd Wright’s Fallingwater house is considered one of the first examples of bioarchitecture, characterized by an organic structure that harmoniously integrates with the surrounding landscape. Other examples include: the California Academy of Sciences in San Francisco, featuring a roof completely covered with vegetation that promotes water and energy savings, and The Edge in Amsterdam, recognized as the most sustainable office in the world for its innovative energy-saving solutions and renewable energy production.

To provide further examples of bioclimatic architecture, we can mention Le Corbusier’s rooftop garden and green facades.

The concept of a rooftop garden was introduced by Le Corbusier, a renowned modern architect, as an integral part of his works. This architectural element involves adding a layer of vegetation on building roofs, creating a green extension above the structure. Le Corbusier adopted the rooftop garden for several reasons. Firstly, it promotes the integration of the building with the surrounding landscape, reducing the visual impact of architecture on the natural environment. Additionally, it provides thermal and acoustic insulation to the building, helping to maintain a comfortable temperature inside and reduce external noise.

From an environmental perspective, green roofs absorb rainwater, reducing the risk of flooding and helping to mitigate the urban heat island effect. Additionally, they contribute to improving air quality through the plants’ photosynthesis process.

One of Le Corbusier’s most famous projects featuring a rooftop garden is the Villa Savoye, one of his iconic works completed in 1931 in Poissy, France. Today, thanks to building design software, it is possible to recreate the Villa and other eco-sustainable buildings in a few simple steps.

Bioclimatic architecture: projects in Italy

Regarding Italian’s bioclimatic achitecture, we can mention the Energy Box in L’Aquila: a building that stands out not only for its high ecological and sustainable standards but also for its humanitarian nature, especially in contexts of great need. It was conceived as a symbol of the area’s rebirth after the devastating earthquake that struck the region. The project was designed by Pierluigi Bonomo, a young local engineer specializing in seismic safety and energy efficiency, with particular attention to integrating renewable energy sources in architecture.

Furthermore, the Zisa Castle in Palermo represents a remarkable example of low-tech bioclimatic architecture, which leverages natural thermotechnical principles to ensure building cooling and ventilation, born over 1000 years ago.

And we cannot overlook the green facades that enhance buildings’ energy efficiency and contribute to environmental sustainability. Not only are they visually pleasing solutions, but they also encompass a range of advantages and benefits:

  • thermal insulation: plants on the facade act as a natural insulator, reducing heat loss in winter and heat gain in summer. This helps maintain a more stable and comfortable internal temperature without excessive reliance on mechanical heating or cooling systems;
  • reduction of the urban heat island effect: green facades absorb part of the solar heat and thermal energy from the surrounding environment, helping to reduce the urban heat island effect in densely populated urban areas. This phenomenon is particularly relevant during summer periods and can help mitigate the effects of heatwaves;
  • improvement of air quality: plants absorb carbon dioxide and other pollutants from the air, contributing to improving the quality of the surrounding air. This is particularly important in urban areas, where air pollution can be significant and have serious consequences on human health;
  • management of rainwater: green facades can absorb rainwater, reducing the risk of flooding and helping to manage surface water flow. This is important to reduce the burden on urban drainage systems and prevent road and urban area flooding;
  • reduction of environmental impact: green facades contribute to urban biodiversity by providing habitats for insects, birds, and other wildlife. Additionally, they reduce the environmental impact of buildings by reducing energy consumption and absorbing carbon dioxide from the atmosphere.

Bioclimatic Architecture - Edificius Project

Bioclimatic Architecture – Edificius Project

Bioclimatic architecture and sustainable design

The concept of bioclimatic design was born with Victor Olgyay, particularly with Design with Climate (1962), a book that laid the theoretical and technical foundations of a design methodology based on the relationship between building and climate. It derives from:

  • bios“: life;
  • klima“: literally “inclination of the earth from the equator to the poles” and in the current sense indicates “the set of meteorological conditions of a specific area“.

Designing following bioclimatic principles means creating sustainable and comfortable buildings, oriented towards energy self-sufficiency. This discipline, an integral part of green construction, considers the entire structure as a unique organism, integrating climatic conditions and human needs. The goal is to create sustainable buildings in the short and long term, capable of adapting even to the most extreme climates. The main features include studying and using local climatic conditions, seeking optimal energy efficiency, and promoting healthy environments.

Energy-efficient design should involve the following phases:

  1. climate analysis and evaluation of effects, highlighting the importance of different climatic elements and any critical issues;
  2. identification of applicable technical solutions;
  3. combination of these solutions with the design definition of the system.

Sustainable buildings bioclimatic architecture

Sustainable buildings bioclimatic architecture

Definition of climatic and meteorological parameters

The elements characterizing weather and climate are the same, but while weather represents a local and momentary combination of meteorological factors, climate corresponds to the types of weather that commonly occur throughout the year in a specific region.

To establish the climate of a region or location, extensive meteorological observations over a long period are necessary. From this long series of data, it is possible to derive the series of meteorological conditions that most frequently occur in different periods of the year, thus obtaining the climate of that region or location.

Climatic information can be evaluated at three different levels, using the area extension considered as a climatic scale. Consequently, we talk about

  • macroclimate;
  • mesoclimate;
  • local climate;
  • microclimate.

In general, the macroclimate is defined as the climate corresponding to vast regions (e.g., macroclimate for the Mediterranean basin, etc.), referring to the average values of geographical and meteorological parameters that correspond to them. A higher level of detail is possible by analyzing less extensive regions, characterized by their mesoclimate (e.g., mesoclimates characterizing coastal and mountain areas).

Going into more detail, we talk about local climate and microclimate: for example, deforestation, urbanization, and land cementation have a significant local impact.

Factors influencing climate

The main factors influencing the definition of a specific climate in a terrestrial region are of astronomical and geographical nature. The Earth’s atmosphere also acts on these factors, generating phenomena such as winds, clouds, and radiation diffusion, etc.

Astronomical factors are responsible for the different angle of incidence of solar radiation in different places and at different times of the year. Earth’s movements combined with the elliptical shape of the orbit, the axis inclination, and the planet’s spherical shape determine a different distribution of solar energy on the Earth’s surface, thus determining the change of seasons, the variation of day and night length throughout the year.

The amount of solar energy incident on a location depends on the time of year and latitude.

Latitude is the fundamental parameter describing the availability of solar radiation, but it is not sufficient to characterize a site’s climate. Local geographical factors such as the presence of water bodies, mountain systems and their orientation, the topographic exposure of the site (greater or lesser protection from winds or marine currents), the nature of the terrain, etc., significantly influence.

To define the climate of a place, you need to consider the physical parameters that determine the conditions of the atmosphere at that site. The main parameters used are temperature and relative humidity of the air, precipitation levels, wind speed and direction, and solar radiation intensity. Due to the variability of meteorological conditions for different variables, values averaged over a long period are used to obtain a statistically significant description, effectively representative of environmental conditions. The time frame should be sufficiently broad, typically around 20-30 years.

Solar Radiation

The primary source of energy for Earth is solar radiation, which reaches the Earth’s surface both directly from the sun and after being scattered by particles (dust, gas molecules, aerosols) in the atmosphere. Thus, there is direct and diffuse radiation.
The direct component arrives from a well-defined direction, while the diffuse component is omnidirectional. The sum of direct and diffuse radiations is referred to as global radiation.

Incident radiation is expressed in terms of incident power per unit area (W/m²) or incident energy per unit area in a certain time interval (J/m² or Wh/m²).

It’s also important to note that the intensity of radiation depends on the angle of incidence according to the cosine law, meaning radiation is greater when the surface it falls on is perpendicular to the direction of sunlight. Typically, weather stations measure intensity on a horizontal surface.

Consequently, radiation intensity depends mainly on the latitude of the location: high intensities occur around the equator in the band between the tropics, where the sun is always close to the zenith. As latitude increases, radiation intensity decreases.

Solar radiation outside the atmosphere remains constant over time, approximately 1353 W/m² (solar constant). However, radiation values at the Earth’s surface are significantly lower due to absorption and reflection by the atmosphere, and especially the longer the solar rays travel through the atmosphere, the lower the intensity of the global radiation that reaches the ground. The length of this path varies with the inclination of the rays, meaning it varies with latitude, season, and time of day.

Radiation intensity also depends on the atmospheric turbidity, i.e., the content of water vapor, dust, particles, and pollutant gases that make up the local atmosphere.

Air Temperature

Temperature is a fundamental parameter in defining the thermodynamic state of the atmospheric air.
It varies greatly in space and time. In a given location, characteristic variations of temperature on a daily and annual scale are a consequence of changes in insolation conditions, although there is a direct dependence on wind and rainfall as well.

The magnitude of the diurnal temperature variation depends on sky cover conditions. On clear days, the large amount of available radiation produces a significant daily temperature variation, while on overcast days, the variation is smaller.

The maximum temperature usually occurs around 2-3 pm, with a delay compared to the maximum insolation. Air, in fact, is not heated directly by radiation but is heated by convective exchange from the ground and other surfaces exposed to the sun.

The minimum temperature occurs during the late night-early morning hours after the Earth’s surface has reached its minimum temperature due to cooling by radiation toward the sky, and solar rays have not yet begun to warm it.

On an annual scale, temperature follows a pattern with a peak about 30-40 days after the period of maximum insolation corresponding to the summer solstice and a minimum about 30 days after the winter solstice, due to the thermal inertia of the system, so that the air changes its temperature after the Earth’s surface has changed it. Consequently, the hottest period of the year is between July and August, while the lowest temperatures are reached in January.

Temperature also varies with altitude, generally decreasing by about 0.5 ÷ 0.8 °C for every 100 m increase in altitude. The thermal description of a site is made using values averaged over time to neutralize exceptional events that are not representative of the local climate. Daily mean temperature, monthly mean temperature, daily maximum and minimum temperature, annual maximum and minimum temperature are defined according to the time interval over which the data are averaged.

The difference between the maximum and minimum temperature recorded over a certain period of time is called the temperature range, and even in this case, it is necessary to refer to average values.

Relative Humidity

When we talk about atmospheric humidity, we mean the amount of water vapor contained in the atmospheric air, as a result of evaporation from mainly seas and oceans. However, all other wet surfaces, vegetation, and smaller bodies of water like lakes and rivers also contribute. The vapor is then distributed over the Earth’s surface by winds.
An air mass cannot contain an unlimited amount of water vapor, but there is a concentration limit function of temperature, which is directly proportional. Beyond this concentration, called saturation, the vapor begins to condense. Often this concentration limit is expressed in terms of the partial pressure of the vapor in the mixture and is defined as the partial pressure of saturation. The moisture content in the atmosphere is mainly expressed as:

Absolute humidity, defined as the ratio between the mass of vapor contained in a certain mass of humid air and the volume occupied by that mass of air; its unit of measurement will be (g/m³);
Relative humidity, the percentage ratio between the amount of vapor actually present in the air compared to the maximum amount that could be present under the same conditions of atmospheric pressure and air temperature. When the air contains the maximum amount of vapor, it is called saturated, and its relative humidity is 100%.
From a practical point of view, the most easily measurable parameter is relative humidity, and it is the most commonly used to indicate the content of water vapor in the atmosphere.

When the air temperature decreases, its capacity to hold vapor decreases, while its relative humidity increases. The temperature at which saturation conditions are reached is called the dew point.

Cloud Cover

The cloud cover of a given site has significant implications for the quantity and quality of solar and thermal radiation from the sun and sky. Cloud presence can be inferred from the relative sunshine index, i.e., the ratio of hours of clear sky to the length of the day. Hours of clear sky are indicated by the time interval during the day when solar radiation reaches a certain value (usually equal to 200 W/m²) that can be recorded by a specific instrument called a heliometer. Using the relative sunshine index introduces the approximation that cloud cover is uniformly distributed throughout the day and even throughout the month, as this index is usually provided as a monthly average value.

Precipitation

The amount of precipitation, along with air temperature and radiation intensity, constitutes one of the fundamental quantities for meteorology. The amount of precipitation in different forms (rain, snow, hail) is expressed in millimeters of water per unit of time (hour, day, year); 1 millimeter equals 1 liter of water per m².
In addition to monthly or annual global precipitation, the intensity of precipitation is also important, i.e., the amount of water fallen in a unit of time (mm/h).

Wind

By wind, we mean movements of air masses caused by differences in atmospheric pressure resulting from different heating of the Earth’s surface (pressure gradient). The parameters characterizing the wind regime of a given site are essentially two: the speed module and its direction. Direction is identified with reference to cardinal points and can be expressed either in degrees (between 0° and 360°, with 0° coinciding with North) or in sectors, usually 8 or 16 (compass rose).
For specific applications, one can also refer to an average wind speed regardless of direction. It should be noted that wind speed, both in terms of module and direction, varies greatly over time. Therefore, it is always good to refer to values averaged over appropriate time intervals.

To indicate wind intensity, one can also refer to the Beaufort wind scale, developed in 1805 for the empirical measurement of wind speed by Admiral Beaufort, and adopted in 1874 by the World Meteorological Committee.

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